Ski binding

ABSTRACT

Quick-release heel hold-down device for ski binding, comprising a heel retaining jaw pivotally mounted on a fixed base member and responsive to the force of a spring constantly urging said jaw upwards to its release position. The resilient return means comprise a spring-loaded piston adapted to hold said jaw in its lower or operative position, and a pivoting member engaging on the one hand said pivoting jaw and on the other hand said piston of said resilient return means. Said pivoting member comprises a control edge in bearing engagement with the operative face of said spring-loaded piston of said resilient return means, said last-mentioned means acting through said control edge for constantly urging said pivoting member in the direction of rotation corresponding to the closing of said jaw. Said pivoting member has two end stable positions corresponding the one to the jaw opening position and the other to the jaw closing position, and said jaw comprises a control lug co-acting with said pivoting member in order to produce a selflocking action against the pressure force developed by said resilient return means in the end position corresponding to the open jaw position.

United States Patent 91 Beyl [451 May 14,1974

[ SKI BINDING v [76] Inventor: Jean Joseph Alfred Beyl, 10

Boulevard Victor Hugo, 58 Nevers,

France [22] Filed: July 24, 1972 [21] Appl. No.: 274,498

[30] Foreign Application Priority Data July 30, 1971 [52] US. Cl 280/ll.35 T [51] Int. Cl. A63c 9/08 [58] Field of Search 280/1 1.35T

[56] References Cited UNITED STATES PATENTS 3,545,780 12/1970 Salomon 280/1 1.35 T 3,620,545 11/1971 Korger 280/11.35 T 3,734.520 5/1973 Kashiokan. 280/1 1.35 T 3,529,845 9/1970 Kanno 280/1 1.35 T

Primary Examiner-Robert R. Song Attorney, Agent, or Firm-Bierman & Bierman France 7127975 [57] ABSTRACT Quick-release heel hold-down device for ski binding, comprising a heel retaining jaw pivotally mounted on a fixed base member and responsive to the force of a spring constantly urging said jaw upwards to its release position. The resilient return means comprise a springloaded piston adapted to hold said jaw in its lower or operative position, and a pivoting member engaging on the one hand said pivoting jaw and on the other hand said piston of said resilient return means.

Said pivoting member comprises a control edge in bearing engagement with the operative face of said springloaded piston of said resilient return means, said last-mentioned means acting through said control edge for constantly urging said pivoting member in the direction of rotation corresponding, to the closing of said jaw. Said pivoting member has two end stable positions corresponding the one to the jaw opening position and the other to the jaw closing position, and said jaw comprises a control lug co-acting with said pivoting member in order to produce a self-locking action against the pressure force developed by said resilient return means in the end position corresponding to the open jaw position.

10 Claims, 7 Drawing Figures PATENTEDMAY 14 I974 SHEET 3 [IF 3 Fig. 6

SKI BINDING The present invention relates in general to ski bind ings and has specific reference to a heel hold-down device therefor, and more particularly to a quick-release device of this character.

This ski binding heel holdldown device is of the type wherein a heel retaining jawis pivotally mounted to a base member adapted to be secured to the ski, resilient means constantly urging said jaw to its normal heelhold down position while permitting the lifting thereof in case a considerable stretching effort where exerted on the skiers leg.

Said resilient means comprise a spring-loaded piston consantly urging said jaw to its lower or operative position through a member pivotally mounted in said base. This pivoting member engages on the one hand the heel hold-down jaw and on the otherhand reacts against the piston of said resilient means. The arrangement is such that for each movement of said pivoting member away from its endmost position corresponding to the lower or operative position of the jaw a return torque takes place along a considerable pivoting stroke.

ln such hold-down devices it is advantageous to produce a pivoting movement of relatively great amplitude during which the heel of the ski boot remains in proper engagement with said jaw, before it is released completely, this following" movement being also referred to as the long-release stroke. However, it should also be pointed out that the return torque remains substantially constant throughout this movement. 7

A number of heel hold-down devices have already been proposed which are designed with a view to meet these various requirements. In these known propositions the pivoting member comprises a cam disposed against the piston of said resilient means and having a contour so designed that a return torque of great amplitude is created during the pivoting movement of this H member in relation to the piston. However, difficulties are encountered for determining the end positions of the movable members, notably the position producing the upward movement of the retaining jaw and wherein the heel hold-down device is open to permit the reinsertion of the corresponding ski boot. Now, holding the retaining jaw in this specific position is of primary of said cam contour; whereby the pivoting member can transmit anelastic return torque to said jaw during a relatively long pivoting movement or stroke. However, when this member has pivoted beyond its position in which the return torque is zero, said stud is caused to leave said'cam notch for engaging a stop under the force of a spring acting on said jaw.

'The return of said heel hold-down device to its closed position is only possible if a certain force is exerted on the retaining jaw in order to cause-the stud to move along the cam contour and re-engage the notch thereof.

It is the essential object of the present invention to provide a heel hold-down device for ski binding, of the .type broadly set forth hereinabove, but of considerably simpler construction and so designed that its jaw has well-defined opening and closing positions. This heel hold-down device isalso so designed that its jaw can accomplish a considerable release stroke during which the resilient means produce a relatively considerable return torque.

The arrangement of this heel hold-down device is also such that even in the upper or release position of said j'aw the return torque exerted by said resilient means remains effective whereby said means can return the jaw to its lower or operative position after a simple control movement, without having to exert a relatively high external stress.

To this end, the heel hold-down device according to this invention is characterised essentially in that the pivoting member comprises a control edge bearing against the piston face of the resilient means, said means constantly acting through said edge against said pivoting member in the direction of rotation corresponding to the locking of the device, in that said pivoting member has two stable end positions corresponding to the opening and closing of said jaw, respectively, and that said jaw comprises a control member co-acting with said pivoting member in order to produce, in the end position corresponding to the open or release position of said jaw, a self-locking action against the pressure force constantly exerted by said resilient means.

Under these conditions, to return the heel hold-down device to its closed position it is only necessary to eliminate this self-locking action by exerting a substantially effortless control action on the tilting jaw. ln fact, thereafter the resilient return means control by itself the return or closing movement of the heel hold-down device..Thus, this control movement may be obtained by a simple contact between the heel of the ski boot and a lug or resetting pedal prov-idedon the jaw.

[n a specific form of embodiment of the heel holddown device according to the present invention the edge controlling the pivoting member extends between two control surfaces of which at least one determines an end position of this member bearing against the piston of the resilient return means, and the control member provided on the retaining jaw proper has a bearing contour engaging, in the open position of the device, said pivoting member in order to produce a self-locking action thereagainst.

To this end and according to a particularly advantageous form of embodiment of the invention, one of said control surfaces intended for hearing against the piston of the resilient return means has not only the function of determining the end position of the relevantpivoting member which corresponds to the closing of said heel hold-down device, but also the function of acting as a bearing surface to the locking member carried by the retaining jaw when this pivoting member is in its other end position corresponding to the opening or release of said device. This self-locking position will thus determine at the same time the other stable end position of the pivoting member.

In another form of embodiment of the present heel hold-down device each control surface adapted to en gage the piston of the resilient return means determines one and the other of said end angular positions of said pivoting member, and another control surface is provided on the periphery of this pivoting member for constituting the bearing surface engageable by the locking member carried by the retaining jaw in the self-locking position with said pivoting member.

The self-locking action may be applied to the movable members in the open position of the heel holddown device by properly shaping the third control surface of the pivoting member and/or suitably shaping the locking member carried by the retaining jaw, by taking due account of the geometrical position of the transverse pins for properly arranging the pivoting member and the jaw in relation to each other. Therefore, a certain freedom is allowed for the practical embodiment of the invention.

In a preferred form of embodiment of the present invention, the intermediate pivoting member consists of a prismatic body having in cross-section the shape of an irregular trapezoidal polygon of which the minor base acts as a control surface for determining the end position corresponding to the downward movement of the jaw, the non-parallel sides of said polygon acting the one as a control surface corresponding to the other end position of this member and as a bearing surface for the control lug or projection or relief portion carried by said jaw, respectively, the control edge of said member which co-acts with the piston of the resilient means being constituted by the edge of the prismatic body which lies between the two control surfaces corresponding to its end positions.

To permit the manual opening of the heel hold-down device of this invention, the latter comprises a control lever pivotally mounted to a pin disposed coaxially to the pivot pin of the pivoting member, said lever being rotatably solid with said pivoting member at least in the direction corresponding to the upward or release movement of the jaw.

However, other features and advantages of the present invention will appear as the following description proceeds with reference to the attached drawing illustrating diagrammatically by way of example various forms of embodiment of the present heel hold-down device. In the drawing:

FIG. I is a vertical section showing a first form of embodiment of the heel hold-down device illustrated in its closed or hold-down position;

FIG. 2 is a similar view showing the device in its open or release position;

FIG. 3 is a diagrammatic view showing the main component elements of the device according to a second form of embodiment thereof;

FIG. 4 is a vertical section showing still another form of embodiment of the device;

FIG. is a vertical section showing a modified form of embodiment of the device illustrated in FIGS. 1 and 2, and

FIGS. 6 and 7 are sectional views of another modified form of embodiment.

In the specific form of embodiment illustrated in FIGS. I and 2 of the drawing the heel hold-down device for ski binding according to the present invention comprises a base plate 1 adapted to be secured to the top surface of a ski. This base plate acts as a slideway for guiding a plate 2 supporting the body or base member 3 of the device of this invention.

At its front end, the plate 2 carries small block 4 adapted to support the heel ofa ski boot when the latter has been properly positioned on the ski. The plate 2 is adapted'to slide longitudinally with said body 3. Now the latter comprises in a manner known per se means for adjusting its longitudinal position. This system compirses generally a rotary bolt 6 rigid with a worm 7 meshing with a rack 5 formed on top of the fixed plate 2.

The bolt 6 is adapted to slide and rotate in the body 3. As to the worm 7, it is fitted in a cavity 9 formed in this body 3 and this cavity 9 also encloses a compression spring 8 constantly urging the bolt 6 backwards.

Due to the meshing engagement between the worm 7 and the rack 5, when the bolt 6 is rotated it causes a longitudinal translation of the complete heel holddown device in one or the other direction in relation to the plate 1 rigid with the ski. However, due to the sliding mounting of the worm 6 in the-body 3, the heel hold-down device can recede resiliently towards the rear end of the ski through a few millimeters against the force of spring 8 if an excessive stress were exerted on the device in this direction.

The body 3 of the device is obtained preferably by casting and comprises at its front end a central recess 10 facing forwards. This recess is bound by a pair of parallel side walls 11 and by a slightly inclined rear wall 12.

The side walls 11 carry a first horizontal pivot pin 13 extending transversely and substantially level with the upper edge of the heel of a ski boot. The function of this pivot pin 13 is to act as a support to a pivoting jaw 14 adapted to engage the top of the rear portion of the heel of the corresponding ski boot. This jaw 14 comprises a lower extension 15 formed with a lug 16 adapted to be' used as a resetting pedal.

On the other hand a torsion or spiral spring 17 surrounding the pivot pin 17 constantly urges the jaw 14 to its raised position shown in FIG. 2.

The jaw 14 is also formed with an integral rear control lug l8 projecting within the recess 10 and adapted to co-act with an intermediate pivoting member 19 disposed between the retaining jaw 14 and the elastic return means incorporated in the device. This pivoting member 19 is in fact pivotally mounted about another horizontal pin 20 also disposed transversely between the two side walls 11 of recess 10, and somewhat spaced from, and at a lower level than, the first pivot pin 13.

The resilient return means contemplated in this device comprise a piston 21 adapted to engage said intermediate pivoting member 19 and urged by one end of a coil compression spring 22. This spring 22 is housed in a bore 23 formed in said body 3 and slidably engaged by said piston 20. The other end of spring 22 reacts against a screw plug 24 engaged in the tapped rear end of said body 3; by rotating this plug in one or the other direction it is possible to-adjust the initial stress of spring 22. To permit the proper identification of the desired adjustment of this compressive force the plug 24 carries a small plate 25 provided with reference marks on its outer surface. This plate 25 slidably mounted in a recess 26 formed to this end in said body 3 is of course prevented from rotating in relation thereto. Under these conditions, the small reference plate 25 is simply anchored to the plug 24 soas to move bodily therewith while permitting its rotation. The value of the adjustment of spring 22 is displayed by the reference mark appearing flush to the outer edge of recess 26.

The pivoting member 19 engaged by the spring loaded piston 21 consists of a prismatic body having in longitudinal section (i.e. substantially as shown in FIGS. 1 and 2) the general configuration of an irregular trapezium. This member 19 extends substantially throughout the width of the recess 10. The minor base 27 of this prismatic member constitutes a control surface engageable by piston 21 when the heel-retaining jaw 14 is in its lower or operative position (see FIG. 1

One of the non-parallel sides of this prismatic member, namely side 28, constitutes another control surface engageable' by piston 21 when the jaw 14 is in its upper or release position (FIG. 2). Now, the edge 29 separating these two control surfaces acts as a control edge coacting with the piston 21 when the 'member 19 is pivoted as a consequence of the upward movement of jaw 14 in order to generate an elastic return torque urging this member to its initial position shown in FIG. 1.

Like the other non-parallel side 30 of the prismatic member 19, it constitutes a control surface adapted to co-act with the control member 18 carried by said jaw 14, as will be explainedmore in detail presently.

To. permit the manual opening or release of the heel hold-down device, a control lever 31 is provided. Preferably, this lever is a U-shaped member having its two side arms or branches disposed on either side of the body.3. The rearor outer ends of these arms are interconnected by a distance-piece 32 formed with an aperture 33 through which a safety belt may be inserted.

At their front-or innerends the two arms of lever 31 are interconnected by a pair of horizontal or transverse rods or bolts 34 extending through the pivoting member 19 and also through a pair of arcuated slots 35 formed in the side walls 11 of the aforesaid recess concentrically to the pivot pin 20.

As clearly shown in FIG. 1, the piston 21 of the resilient means is urged by spring 22 against the control surface 27 of pivoting member 19 and also against the edge 29, in order to hold this member 19 in a first stable end position corresponding to the lower and operative position of jaw 14. In fact, the torsion spring 17 constantlyurges the control member 18 ofjaw 14 for bearing engagementwith the control surface 30 of pivoting member 19. In this position these two members co-act at a contact point somewhat spaced from the first transverse pivot pin 13. Under these conditions, the jaw is kept in its lower or operative position.

However, if a force P directed upwards in a direction substantially normal to the ski surface is exerted on the jaw 1-4 and if this force exceeds the adjustment threshold preset by. means of the screw plug 24 (for example as a consequence of a fall of the skier) this force will tend to tilt-the jaw about the pivot pin 13 in the direction of the arrow Fl.

The jaw control lug 18 will thus cause the pivoting member 19 to rotate in the direction of the arrow F against the pressureexerted by piston 21 on the control surface 27. However, as this member 19 begins to rothe force! is applied only during a relatively short time, for example as a consequence of a shock.

But if this force F continues to be exerted, the jaw 14 will be caused to rotate until the end portion 36 of its control lug 18 engages the corresponding control surface 30.

In fact, due to the contour provided for the end portion of this member and/or its geometrical position in relation to the pivot pin 20, the latter is self-locked together with the pivoting member 19. Under these conditions, the member 19 is retained in the other stable end position contemplated therefor.

In fact, the piston 21 of the resilient means continues to exert an elastic pressure on this member but with a greater force, although through a shorter lever arm. However, this action is prevented by the jaw control lug 18. Therefore, any untimely return of this jaw 14 and of the pivoting member l9to their closing positions is precluded. Thus, the retaining jaw 14 is held in a welldefined, stable position permitting a convenient and proper positioning of the ski boot.

While the jaw 14 is still in its upper or inoperative position, it is possible to properly re-position the heel of the ski boot by simply accomplishing an initial and substantially effortless manoeuvre for discontinuing the self-locking action and producing a servo-action closing movement of the heel hold-down device.

This action may be obtained for example by simply causing the underface of the ski boot heel to engage the resetting pedal 16. In fact, when the control lug 18 is released from its locking action exerted against the pivoting member 19, the pressure exerted by piston 21 thereagainst causes the pivoting member 19 to pivot in the direction of the arrow F so as to restore this member in its first stable end position shown in FIG. 1. Now, during this movement the pivoting member 19 actuates the jaw control lug 18 in order to restore the latter to its lower, operative position. Consequently, the return of the jaw 14 to its operative position is obtained without exerting any closing effort, in contrast to the mode of operation of other known heel hold-down devices.

Another outstanding feature characterising the heel hold-down device of this invention is that it permits a relatively long heel release stroke or movement with only a relatively short stroke of spring 22.

The device of this invention may be opened manually by lifting the lever 31 in the direction of the arrow F. In fact, this movement causes the lever to pivot about the pivot pin 20 and therefore the rotation of pivoting member 19 and the latter permits the upward movement of jaw 14 due to the force of spiral spring 17 until the jaw is in its uppermost position in which a selflocking action takes place'between its control lug 18 and the pivoting member 19..

FIG. 3 illustrates diagrammatically the relative positions of the essential component elements of the device in a modified form of embodiment of the device of this invention.

In this figure, the same reference numerals as in the preceding form of embodiment designate corresponding or equivalent elements, but with the addition of the letter a.

In this second form of embodiment the crosssectional configuration of the pivoting member 19a differs and the arrangement is such that the control surface 27a engaged by piston 21a in the closed or operative position of the heel hold-down device acts at the same time as a bearing surface to the control lug 18a carried by the pivoting jaw 14a. In the upper or release position of this jaw the end portion 36a of said control lug engages the control surface 27a as shown in dashand-dot lines in FIG. 3, so as to produce the selflocking of the intermediate pivoting member 190. As in the preceding example, the pivoting member 19a is locked against movement in its second stable end position by said control lug 18a, this second position corresponding to the upper position of said jaw although the pivoting member 19a is still responsive to the pressure of piston 21a.

In this modified form of embodiment no second control surface like the surface 28 of the preceding form of embodimemt is contemplated for engagement by the piston in this specific position. In fact, in the arrangement shown diagrammatically in FIG. 3 the piston 21a remains in engagement with the control edge 29a of pivoting member 19a.

Thus, to return this member 19a to its initial position, it is only necessary to cause the jaw 14a to pivot slightly so that the end portion 36a of control lug 18a will no more exert its self-locking action with respect to the pivoting member 19a. In fact, the pressure produced by the spring will subsequently cause this member to return to its initial position and consequently the pivoting jaw will resume its lower, operative position.

It may be emphasized that the self-locking action produced in the second end stable position of pivoting member 19 or 190, i.e., the position corresponding to the upper-or release position ofjaw 14 or 140, may also be obtained by properly arranging the transverse pivot pins 13 and 20 with respect to each other and/or selecting a suitable contour for the bearing areas between the pivoting member 19 or 190 and the control lug 18 or 18a carried by said jaw.

FIG. 4 illustrates a third form of embodiment of the present invention wherein the general structure is substantially unchanged, so that the same reference numerals completed by the letter 12 are used for designating similar or equivalent elements of the device.

The device shown in FIG. 4 differs from that of FIGS. 1 and 2 by the fact that the manual release lever 31b is mounted for free rotation about the pivot pin 20b.

In an eccentric position in relation to this pin 2012 the two side arms of lever 31b are interconnected by a single horizontal bolt 34b engaging an arcuate aperture 35/) formed in the side walls 11 and concentric to said pivot pin 20)). This bolt engages freely the pivoting member 1912 in the closed position of the heel holddown device. On the other hand a spring (not shown), for example a spring wound about the pin 20b, constantly urges the lever 31b to its normal lower position, i.e., parallel to the ski.

When it is desired to open the device manually, for example for binding a ski boot in position, it is only necessary to pull this lever 3112 so as to pivot same in the direction of the arrow F whereby the bolt 34b rigid with said lever will move along the curved aperture 351) while pushing in front of it the pivoting member 1912 against the piston 21 while compressing the spring 22. This movement is attended by the upward movement ofjaw 14 until its control lug 18 is in its selflocking position shown in FIG. 4.

When this end stable position is obtained, the lever 31h may be released. Under these conditions, this lever will return automatically to its initial closed position due to the action of a spring (not shown), and the jaw 14 remains in its raised position.

In this modified form of embodiment it will be seen that the force P causing the upward movement of jaw 14 is not attended by a movement of lever 3112. This is due to the fact that this lever is mounted for free rotation with respect to the pivoting member 19b, the latter being free to rotate about its axis while the lever remains stationary. This feature is particularly interesting since the lever 311) will not follow the many up and down movements of the jaw which are caused by the absorption of recurrent shocks and stretching efforts normally produced when skiing. The same applies in the case of a fall attended by a complete release of the ski boot heel.

FIGS. 6 and 7 illustrate another modification of similar character, i.e., a form of embodiment characterised by the mounting of the corresponding release lever 31c for free rotation about the pivot pin 200.

However, this modified form of embodiment departs from the one shown in FIG. 4 by the specific configuration of the pivoting member 19c acting as an intermediate element between the jaw 14 and the piston 21 of the resilient return means. In fact, the contour of this member 19c corresponds substantially to that ofa trapezium having undergone a certain deformation. But, of course, this member still comprises a control edge 29 co-acting with the piston 21 for returning the jaw 14 to its loweror operative position.

On its front face, the pivoting member comprises a notch 40 having two dwell portions or cavities engageable by the transverse bolt 34c interconnecting the two sides of the opening lever 31c.

Of course, this bolt engages likewise an arcuated aperture formed in the side walls 11 of the body, concentrically to the pivot pin 20c. Moreover, this bolt 34c is adapted to operatively interconnect the lever 31c and pivoting member 190, for pivoting the latter' in the direction. of the arrow F when the lever 31c itself is raised in the direction of the arrow F The width of notch 40 corresponds to the magnitude of the permissible angular stroke of pivoting member 190 during the upward or release movement of jaw 14 against the resistance of the elastic return means. In fact, said bolt 34c is then positioned opposite the notch 40 as shown in FIG. 7. However, when the release or upward movement ofjaw 14 is controlled by means of the manual control lever 310, the bolt 34c remains of course at the same end of notch 40 as when said lever is in its lower position.

In the various forms of embodiment of the present heel hold-down device adequate means may be provided for adjusting the vertical position of jaw 14 as a function of the thickness of the heel of each ski boot. To this end, this jaw may be detachably mounted to its support 15 and secured thereto in a known manner, for example by means ofa screw permitting the adjustment of its vertical position. But it is also possible to provide a plurality of shims 4 having different thicknesses,

adapted to fit on said support or on a suitable support member carried by the front end of plate 2. Another possible solution to this problem consists in adjusting the vertical position of the jaw by inserting shims of different thicknesses on the abovementioned block 4.

To facilitate the movement of the various movable elements in relation to each other at least some of them may be provided with rollers. Thus, as illustrated diagrammatically inFlG. 5, the pivoting member 19 may be provided with a roller 37 at the'location of its operative or control edge co-acting with the piston 21 of the resilient return means.

similarly, a roller 38 may be provided on the operative contour of the control member or lug 18 carried by the tilting jaw 14.

Other modifications and variations may be brought to the exemplary forms of embodiment of the invention which are shown and described herein by way of illustration, without inasmuch departing from the basic principles of the invention as set forth in the appended claims.

What I claim is:

l. A heel hold-down device for a ski binding comprising a base member adapted to be fixed on a ski, a heel retaining jaw having a contacting portion adapted to bear against the heel and pivotally mounted on said said ski and a release position, a pivoting member mounted on said base member and adapted to pivot about a second axis substantially parallel to and spaced apart from said first axis, said pivoting member having a control edge, a resilient return means affixed to said base member and comprising a piston spring loaded toward and bearing against said pivoting member whereby said jaw is resiliently held in said operative position, a lug on said jaw bearing against said pivoting member at a bearing portion, said lug and said contacting portion being on opposite sides of said first axis and said control edge and said bearing portion being on opposite sides of said second axis, said pivoting member having a first and a second end stable position, said pivoting member being in said first position when said jaw is in said release position and said pivoting member being in said second position when said jaw is in said operative position.

2. A device according to claim 1 wherein said control edge is disposed between a first control surface and a second control surface formed on said pivoting memher, said first surface stably bearing against said piston when said jaw is in said release position, said lug having a bearing contour adapted to stably bear against said bearing portion when said jaw is in said release position.

3. A'device according to claim 2 wherein said second surface stably bears against said piston when said jaw is in said operative position, said lug stably bearing against said bearing portion when said jaw is in operative position.

4. A device according to claim 3 wherein said pivoting member has a substantially prismatic configuration with a cross-sectional contour corresponding substantially to an irregular trapezium having a minor base and a first non-parallel side and a second non-parallel side, said minor base constituting said second surface, said first side constituting said bearing portion and said second side consituting said first control surface.

5. A device according to claim 1 comprising a manual release lever pivotally mounted for rotation about said second axis, said lever adapted to pivot between an concentric to said second axis, said bolt in said aperture and adapted to engage in said pivoting member while pivoting towards said upper position.

7. A device according to claim 5 wherein said leverv comprises'two substantially parallel spaced apart side arms extending outwardly from said base member, the outer ends of said arms being connected, the inner ends of said arms being connected to said pivoting member by at least one bolt extending through said pivoting member and adapted to travel in apertures in said base member.

8. A device according to claim 3-wherein said second control surface also acts as said bearing portion.

9..A device according to claim 1 wherein said piston is reciprocable toward and away from said pivoting member.

10. A device according to claim 1 wherein there is provided a spring bearing against said jaw and urging it towards said release position. 

1. A heel hold-down device for a ski binding comprising a base member adapted to be fixed on a ski, a heel retaining jaw having a contacting portion adapted to bear against the heel and pivotally mounted on said base member and rotatable about a first axis between an operative position wherein the heel is held down on said ski and a release position, a pivoting member mounted on said base member and adapted to pivot about a second axis substantially parallel to and spaced apart from said first axis, said pivoting member having a control edge, a resilient return means affixed to said base member and comprising a piston spring loaded toward and bearing against said pivoting member whereby said jaw is resiliently held in said operative position, a lug on said jaw bearing against said pivoting member at a bearing portion, said lug and said contacting portion being on opposite sides of said first axis and said control edge and said bearing portion being on opposite sides of said second axis, said pivoting member having a first and a second end stable position, said pivoting member being in said first position when said jaw is in said release position and said pivoting member being in said second position when said jaw is in said operative position.
 2. A device according to claim 1 wherein said control edge is disposed between a first control surface and a second control surface formed on said pivoting member, said first surface stably bearing against said piston when said jaw is in said release position, said lug having a bearing contour adapted to stably bear against said bearing portion when said jaw is in said release position.
 3. A device according to claim 2 wherein said second surface stably bears against said piston whEn said jaw is in said operative position, said lug stably bearing against said bearing portion when said jaw is in operative position.
 4. A device according to claim 3 wherein said pivoting member has a substantially prismatic configuration with a cross-sectional contour corresponding substantially to an irregular trapezium having a minor base and a first non-parallel side and a second non-parallel side, said minor base constituting said second surface, said first side constituting said bearing portion and said second side consituting said first control surface.
 5. A device according to claim 1 comprising a manual release lever pivotally mounted for rotation about said second axis, said lever adapted to pivot between an upper position corresponding to said release position and a lower position corresponding to said operative position, said lever being rotatably coupled to said pivoting member at least while pivoting toward said upper position.
 6. A device according to claim 5 wherein said lever carries a bolt substantially parallel to said second axis, an arcuate aperture in said base member substantially concentric to said second axis, said bolt in said aperture and adapted to engage in said pivoting member while pivoting towards said upper position.
 7. A device according to claim 5 wherein said lever comprises two substantially parallel spaced apart side arms extending outwardly from said base member, the outer ends of said arms being connected, the inner ends of said arms being connected to said pivoting member by at least one bolt extending through said pivoting member and adapted to travel in apertures in said base member.
 8. A device according to claim 3 wherein said second control surface also acts as said bearing portion.
 9. A device according to claim 1 wherein said piston is reciprocable toward and away from said pivoting member.
 10. A device according to claim 1 wherein there is provided a spring bearing against said jaw and urging it towards said release position. 